Rechargeable batteries for electronics, transportation and grid energy storage commonly have poor charge acceptance and suffer from excessively long charge time, especially at subfreezing temperatures, due to sluggish electrochemical kinetics and transport processes occurring in the battery cell. Charging batteries at reasonable rates in cold weathers are either impossible to carry out or incur much shortened battery life. For example, the biggest problem for charging lithium-ion batteries at low temperatures is the lithium plating in the graphitic anode. The deposited lithium reacts quickly with the electrolyte leading to irreversible capacity loss. Furthermore, the metallic lithium grows in dendrite form, creating the possibility of penetrating separator and shorting the cell internally. To avoid lithium plating, lithium-ion batteries are charged at very low rate (C/10 or less) at low temperatures, which requires tremendous amount of time to be fully charged.
The long charging time poses a great disadvantage to energy storage solutions, especially electric vehicles (EV). Compared to traditional gasoline-powered vehicles whose fuel tank can be filled up in less than five minutes under all conditions, EV requires hours to get a full recharge in cold weathers. Fast charging is essential to enable public charge stations and battery-powered electric vehicles.
Because of high sensitivity of battery charge acceptance to temperature, charging time can be reduced by heating rechargeable batteries to a near room-temperature range suitable for fast charging. Conventional battery heating systems, however, heat the battery externally by using convective air/liquid heating or thermal jackets, where heat slowly propagates from the exterior into the electrochemical reaction interface inside the battery. Such processes suffer from long heating time and significant heat loss to the surroundings.
Accordingly, a continuing need exists to reduce the charging time of a rechargeable battery without deleteriously affecting the battery.